The modules and cells tested were produced at Qcells’ pilot production line in Bitterfeld-Wolfen, Germany, using “exclusively mass-production processes for cell and module fabrication,” the company said. The site is supported by funding from the German Federal Ministry for Economic Affairs and Energy (BMWE), the state of Saxony-Anhalt and the European Union, through project PEPPERONI.

“Hitting these milestones means we are getting closer to bringing a product to market that is reliable, saves money and works better,” said Fabian Fertig, head of tandem R&D at Qcells Germany.

The company added that the certifications are “proof that Qcells is getting closer to delivering a product that meets stability and standardisation measures critical to determining if a product is commercially ready.”

Qcells’ tandem products are based on a two-terminal configuration, with a silicon bottom layer using the company’s Q.ANTUM passivated emitter rear contact (PERC) technology, and a perovskite top layer. The modules used tandem solar cells on full-area M10 substrates.

The solar industry has been trying to commercialise perovskite tandem technology for years, though efforts have gathered pace in recent times. The material can absorb a wider range of the light spectrum than silicon, potentially allowing for significantly more efficient solar modules and greater power yield. However, it is a volatile material that degrades when exposed to light, air and water, at a rate which has made it unviable for commercial solar deployments.

Various companies as well as Qcells have made strides in commercialising tandem technology. Notably, British firm Oxford PV has made commercial strides with its heterojunction (HJT)-based silicon-perovskite tandem technology, with partnerships with Fraunhofer ISE and licensing agreements with US-based First Solar and Chinese solar manufacturing giant TrinaSolar.